Apparatus for reclaiming unvulcanized rubber scrap, or the like, containing fiber



P. J. DASHER March 8, 1960 2,927,342 APPARATUS lFOR RECLAIMING UNVULCANIZED RUBBER SCRAP, OR THE LIKE, CONTAINING FIBER Original Filed Harsh v14, 1951 3 Sheets-Sheet 1 Amm mH m5 V A WD @AW lv. L w D.. y B %\mfl1l Vl N\QQ\G use@ e l Vl I4 V ATTYS.

P. J. DASHER March 8, 1960 2,927,342 APPARATUS PoR RECLAIMING UNVULCANIZBD RUBBER SCRAP, 0R THB LIKE, CONTAINING FIBER 3 Sheets-Sheet 2 Original Filed March 14, 1951 /,f/ f /I1 LIT@ v 6 NNN. \N\ 42C N .I.. W4 E l 1% ws I I ||H Q Q\\ VIIUI f f ww. f -fr wwf E QB NQ BQ E..

JNVENToR. PAUL J. DASHER A) A L.

ATTYS.

P. J. DASH ER March 8, 1960 2,927,342 APPARATUS FOR RECLAIMING UNVULCANIZED RUBBER SCRAP, OR THE LIKE, CONTAINING FIBER Original Filed March 14, 1951 3 Sheets-Sheet 5 United States Patent Q This invention relates to apparatus for reclaiming fiber-containing rubber scrap, or the like, and, more pa.- ticularly, is concerned with apparatus for removing from plastic material such as rubber, rayon, cotton, orV like fibers.

lt has been proposed many times heretofore to employ acid or acid vapor for removing cotton or other fibers from plastic, such as unvulcanized rubber. However, so far as I am aware, none of these known methods have met with widespread or continued commercial success,

and none of these methods are employed today in the e rubber industry, for example, in order to salvage or reclaim rubber from scrap including vegetable and like fibers. The lack of use of known acid-treating techniques in the rubber industry exists in spite of the fact4 that many, many tons of vegetable fiber-containing, unvulcanized rubber scrap results every day in` the manufacture of various friction-containing rubber products, such as tires, mechanical goods, V-belts, and boots and shoes.

It is my opinion that the rubber industry, which,lfrom time to time, has tried to render commercially practical acid vapor treating techniquesY for removing vegetable bers, has finally discardedall known methods as impractical and unsatisfactory because of expense of-treatment, difficulty of maintaining treatment conditionsA uniform, lack of completeness of treatment, that is, lack of removal of all vegetable fibers, expense of maintenance of equipment, and lack of maintenance of proper operating conditions, and specifically temperatures, during treatment.

Of course, the rubber industry does employ successfully rubber reclaiming processes of the alkali type on vulcanized rubber which reconditions the vulcanizedrubber to a semi-unvulcanized state, for example, so that it can be mixed with unvulcanized rubber, compounded, and subsequentlyV vulcanized. These known reclaiming operations on vulcanized rubber are often performed upon rubber containing vegetable fibers, with the fibers being converted to ash, which is usually washed outv of the reclaimed rubber. These successful alkali processes for reclaiming vulcanized rubber should not be confused with the acid vapor methods of the present invention and those discussed above of the prior art for reclaiming un-` vulcanized rubber scrap, and, particularly, the removal of vegetable iberstherefrom.

It is the general` object of my invention to avoid and overcome the foregoing and other difhculties of and objections to known apparatus for reclaiming unvulcanized rubber containing fabric by the provision of im proved, inexpensive, readily handled apparatus for com-y mercially andin production quantities reclaiming unvulcanized rubber,Y and the like, and for removing vegetable fibers,` such as Yrayon and` cotton.`

Another object of my invention is to provideV substantially automatic apparatus of relatively inexpensive character'for rapidly and continuously, and with @minimum of supervision, removingvegetable Yfiber from unvulcanized rubber. l

Another object of my invention is. the provision of an improved apparatus for recovering acid after the scrap treating process.

Another object of my invention is to provide apparatus for treating rubber scrap, and the like, in which the acid vapor employed in the treating process is derived from a water solution of the acid gas in a concentration such that when the acid vapor engages the scrap, it will have a dehydrating effect on the scrap and with the resulting acid gas and water vapor in contact with the scrap being substantially constant boiling in character, ie., in the neighborhood of 20.2% acid gas present.

Another object of my invention is theV provision of a treating apparatus of the character described wherein the temperature of the scrap and of the acid vaporV is carefully controlled along a treating path to. create a series of separate zoneswhich blend one into the other, and with the temperature of the stock at all times being kept below the temperature of the acid vapor.

Another object of my inventionis to. provide a treating apparatus of the general type referred to above in which the heat at the end of the treating path where the vapor first engages the scrap is relatively high to create a drying zone, the heat then gradually dropping off as the vapor moves along the path to create a fabric-reacting zone and an absorption zone, and then the heat building back up during the last portion of the travel ofthe gas. over the scrap to substantially the temperature of the drying zone to create are-evaporation zone.

Another object of. my invention is` to-provide apparatus for the processes and` methods described and wherein adjustments4 can be readily made to control factors of time of reaction, temperature, and. concentration whereby quality production, reclaiming, isV consistently achieved.

In the apparatus of the invention, I employ an acidresistanty tube which is journalled. for rotation about its own axis, usually at a selectively variable speed, and with the tube being preferably adjustably supported at: a selected angle withthehorizontal. Vapor supply, means are connected to the lower end of the tube, and the acid vapor is drawnoutthe upper end of the tube with jet# scrubbing means, or the like, for. applying a. sucking action to the tube.. ScrapA supply means. areV connected to the upper end-of thetube and may include centrifugal feed means. The` tube carries vanes for agitating. the scrap as it moves down the tube, and the entire tube is surrounded by aninsulating hood. A plurality of*` independently controllable. heatingelements are positioned between the hood land tube for. establishing, a plurality of heat zones along the length of the tube, Acidrecovery means are providedV for salvaging as much of the treating acid as possible.

For a better understanding of my invention, reference should be had to the accompanying drawings, wherein:

Fig. 1 is a schematic layout of one typical embodiment of the apparatus of my invention in its entirety and capable of performing the improved method of my inveution;

Fig. 2 is a side elevation, partially broken away, of the processing. tube forming a part of my invention;

Fig. 3 is a vertical transverse cross-sectional View of the` processing tube of Fig. 2, and taken substantiallyvon line lli-III of Fig. 2, and on a slightly larger scale;

Fig.` 4.is an end view of the processing tube, taken substantially onV linevIV-IV of Fig. 2, and on aslightly larger scale;

Fig. 5 is a fragmentary sectional view taken on lineV V-V of Fig. 2` and illustrating detailsof the centrifugal feed means for the scrap;

Fig. 6 is an enlarged fragmentary sectional view taken substantially on line VI-v-VI .of Fig. 2 and showing a labyrinth seal at one end of the processing tube;

Fig. 7 is a diagrammatic illustration of the processing tube of Fig. 2 and illustrating the controlled heat zones thereof; and j Fig. S is a graphical representation of the `treating temperatures in the variousnzones of Fig. 7, and likewise, Fig. 8V supplies additional'information Yas to the Vtemperatures of the acid vapor and thescrap.

The principlesY of my invention are broadly applicable to the removal of cellulose from plastic in any of a variety of forms, but are specifically adapted to the removal of Vegetable liber from'unvulcani'zed rubber scrap. For purposes of simplilication, the invention will beY described in conjunction with operations upon rubber, but the scope of the invention is not to beso limited unless specifically stated.

In thetdrawings, and'having particular reference to Fig. l, thernumeral 10Y indicates a plurality of storage compartments or bins for receiving rubberV scrap or Aother similar materials to be reclaimed, and from the storage bins the rubber ytravels by conveyor, truck, or the like, to abale-cutter 12 which cuts the scrap into blocks of a size which can be conveniently handled.V 'The blocks of scrap travel by suitable conveyor or hand truck to one or more cracker mills 14 of known type and character which break up the blocks of scrap into rough, coarse sheets, which in turn are conveyed or otherwise carried to rotary knife cutters 16.

The rotary knife cutters 16 are preferably employed'in pairs, two cutters being positioned at righ-t angles to each other in the manner shown in Fig. 1v sothat a rough sheet of scrap fed into the Vfirst cutter, resultsrin the sheet being Vcut into a plurality of narrow strips which then pass to the second cutter at 90 soY that the strips are cut into small pieces. In fact, the scrap should beV broken up by the process described so that all particles of the scrap will now pass through approximately a 2;/8" screen. This breaking up or comminuting of the scrap to relatively small particle size insures thatrthe vegetable fibers or fabric embedded in the scrap are exposed` at least at their ends on one or more surfaces of the scrap with no piece of the scrap or of the vegetable fibers being very long whereby the vegetable fibers are adequately exposed to attack by the acid vapors, as hereinafter described. Y

From the rotary knife cuttersY 16, the broken-up scrap is passed, usually by an air conveyor 18, to a storage bin 20.V Preferably this storage bin 20 is of the cyclone or blower type so that, should any light pieces of the fabric 'have been mechanically removed from the rubber by the previously described treating process, these porchanically separate the rubber scrap'from thehfabricv which has been attacked by the acid vapors in the processing tube ,22; Frorn'the hammer mill 24, the rubber scrap passes to a screen 26 which is vibrated to separate out and discard objectionably large particles of scrap. The material then passes to the cyclone-separator 30, of known construction, which centrifugally and with the aid of air separates the relined scrap from the hydrolized fabric or liber, separate conduits receiving the refined scrap and the hydrolized benl The liber is salvaged as Well astherscrap and can be used as a ller .forrubber or plastic or'as cellulose having arlong chain length. y

It will be understood that acid'vap'oris passed through thev processing tube 22, preferably ina direction' opposite to the flow of scrap therethrough, and thepacid vapor 4 Y l is obtained from acid carried in a storage tank 32 from which it is lifted by a pump 34, passed through suitable indicating means, such as a gravity indicator 36 and a ow meter 38, to a vaporizer or boiler 40, from which the acid vapor is conducted bya suitable Yacid-resisting pipe to the tubelZZ.

From the processing tube 22, the acid vapor is withdrawn usually by suction and by a conduit 41 ofacidresistant type to a condenser 42 which condenses a'large proportion of the acid and water* vapor back'to liquid acid which flows back to'the storage tank 32 by way of conduit 43. Any uncondensed vapor'passes to a cyclone separator Y44V whichY removes any fabric that might be -pulled into the separator, such material passing to a storage tank 46. Fume scrubbers 48 of the jet type draw the remaining acid vapor fromv the separator 44 into separating boxes 50 and simultaneously condense the vapor, the condensed liquid flowing by conduit 52 back to the acid storage tank 32. The fume scrubbers 48 and separating boxes A50 are 4connected in series in the manner illustrated to insure that no acid vapor fumes escape into-the atmosphere. Conduit 42 and separator 44 may beinsulated to help avoid condensation except at the condenser 42. An. unusual feature ofthe action of the fume scrubbers 48 is that theseare driven in their jet action by liquid acid taken from the storage Itank 32 by pump 49 andr conduit 51. Also, it might be noted here that instead of drawingthe acid vapor with Va suction action through the processing tube 22, I may use a forced draft with a llower fanor fans.

Referring now to Figures 7 and 8 of.V the drawings, and particularly considering the improved reclaiming Vmethod( of my invention, Fig. 7 diagrammatically illustrates the travel ofthe scrap. along'an'Y elongated path' provided by the processing. tube 22, and Awith the acid vapor preferably moving through the tube in a direction opposite to the travel of the stock. I' have divided my processing tube into a series of eight zones and'independently Vand individually control the temperature ofV each one of the eight zones` so as to` obtain an exact control of temperature during the `treating-process. Zones 1 and 2 comprise a re-evaporation zone; zones 3, 4 and 5 constitute an absorption zone; zones 6 and 7 comprise a cellulose-reacting zoneyand zone 8, a'dr'ying zone.

Now lookingcat the graph of Fig'qS, the zone of travel is shown as the abcissa, the ordinate is shown in terms of zone thermostat temperature in degrees Fahrenheit. The resulting curves aregrespectivelyga solid line showing the zone temperatures forthe" treatment of tires and mechanical4 goods scrap', the chain-dotted line for boot and shoe scrap, and the dotted line for .V-belt scrap. It will be noted that the solid line curverin Fig. 8 shows a temperature in zone 1 of approximately 325 F., this gradually dropping down tora temperature of about 250 F. in zones 4 andzS, and building back up to a temperature in zones 7 and 8 of somewhat over 300 F. and usually in the neighborhood of 325 F.. Boot and shoe scrap Vtreatment involves zone temperatures which are down some 30 F. or so from the zone temperatures used for treating tires and mechanical goods scrap, for example, a temperature in zoneY 1 of about 290 F. gradually decreasing to zones 4 and 5 to a temperature of 'about y210 F. and building back up to a temperature of aboutr290 F. in zones 7 and 8, all as indicated by the chain-dotted line. The dotted line representing the zone temperatures for the treatment of V'bel=t scrap, unusually Yhighin rubber,is some 10 F. to'15f Ff lower than the zone temperatures' for *the treating ,of boot and shoe scrap, and' involves,` for example, Yabout a 275 F. temperature inzone 1 gradually reducing to a temperature of about200 F. in. zones, 4 andy 5, and building backup :to aboutla 275 Ratemperature in zones 7 and 8.

'Fie 3 iS 21150 Qf interest in illustrating that the Starting anexa-1a temperature of the scrap in zone 1 is from about 90 F. to about 120 F., and'during the passage offthe scrap through the processing tube, the temperature of the stock graduallyclimbs until the finishing temperature of the stock is as shown, namely, about 175 F. maximum for scrap from tires and mechanical goods, about 150 F. maximum for boot and-shoe scrap, and about 135 F. maximum for V-belt scrap. Fig, 8 also illustrates that the starting temperature of the acid vapor is between about 200 Rand about 240 F., and the finishing temperature of-the vapor is between about 150 F. and about 180 F.

Several-important characteristics of my improved process reveal themselves from a study of Figures 7 and'S. ln the first place, it becomes evident that in my process the scrap being treated is always at a temperatureV less than the temperature of the acid vapor employed to treat the scrap. This is important for the reasonthat the acid vapor tends to condense on the stock, and allows the stock to be treated at a minimum temperature to thereby.- avoid burning or vulcanization of the rubber ofthe scrap while insuring the maximum of chemical action upon the cellulose bers of the scrap. lt should be noted here that the action of the acid vapor upon the fibers is one of hydrolysis in which two chemical reactions-compete. The first of these reactions is merely the de-polymerization (shortening of chain length) ofthe cellulose molecule.V The second reaction is the actual hydrolysis-of the cellulose molecule to sugar, which is objectionable from a reclaim standpoint. By keeping the temperature on the cellulose low as above described, I am able to confine the treatment of the cellulose largely to the first reaction described, without the second reaction ever getting a chance to get really started.

A particularly important part of the action described in the preceding paragraph is effected by the use of a mineral acid, and specifically hydrochloric acid of a concentration between about 21% and about 28%. It is known, of course, that hydrochloric acid of a HCl concentration of 20.27% is constant boiling in character, boilingl about 110- C., and the acid vapor contains substantially the same percentage of HCl as the liquid acid. When hydrochloric acid is concentrated up to contain the limit ofabout 39% HCl, the boiling point is lowered and the acid vapor is largely HC1. At least certain of the advantages of my invention can be achieved by using HCl gas alone, as, for example, in the treatment of very wet scrap within the limits of the results to be achieved as discussed in the following paragraph.

I have discovered that using an acid concentration of between about 21% and about 28% HCl, and usually in the neighborhood of about 25% HCl, I obtain a very definite drying and dehydrating action upon the rubber scrap being treated. Ordinarily there is a considerable amount of water present in the scrap, for example, on an average about 8 pounds of water in 100 pounds o f scrap, and when I employ an acid having a concentration within the limits specified, then the acid vapor ends up on the scrap ata substantially constant boiling point concentration. In other words, the acid vapor absorbs the water present in the scrap, and this additional water in the acid vapor brings the HC1 concentration to approximately the 20.2% HC1, namely, that of a constant boiling point mixture. Thus, the processing tube acts as a drying tube, and allows the scrap to be run at a lower temperature than with other known processes. It will be understood that in treating scrap havingY a high water content, for example, more than 8 pounds of water to 100 pounds of scrap, then Ipuse an acid having a concentration up towards 28% HCl, and in treating a scrap having a low water content, Iv use an acid having a concentration of down towards 21% HC1'.

I have likewise discovered that it is sometimes advantageous, for example, when working with difficult scrap, to employ a wetting agent on the scrap prior to treatment withV-thevacidvapor. ll have found wetting agents satisfactorywhi'chare selectedfrom thepolargr'oup's, such as amines'and `sulfonates which are active in highly concentrated'acid solutionsand which are stable for at least one minute ata temperature not to exceed.v 225 F. I employ a wetting agent of the type indicatedand in an amountof about .05 of 1% ofthe-weight of thescrap and spray the. wetting agent.v on the scrap in the cracker mill orv atsome point beforethe scrap passes to the treating tube. The wetting agent improves the. condensing action of the acid vapor on the scrap and the acid` action inpenetratingupthe cords of the. fabric in the scrap is enhanced.

Another important criterionin mytimproved reclaiming process is the ratio of the totalvolume of acid gas to the total Volume of scrap. Stated more specifically, to one volume of scrap, which runs about 20 pounds per cubic foot bulk density, I use at least about 8-volumes of acid gas. From a practical standpoint, I may use up to about 20 volumes ofacid gas, and greater amounts than this usually merely serve to provide an excess of gas which, except for increasing the drying eect on the scrap, serves no useful purpose. Still more specifically, in a typical days run, I employed-.113 gallons of `acid to treat about 24,000- pounds ofV stock. From a practical operative standpoint, the limits should be such that the acid gas volume usedis sucient to adequately perform the treating action on the fiber content ofA any given scrap being treated.

Having reference now to Figures 2 to 6 of the drawings, the numeral, 22 indicates generally the processing tube to which are secured at spaced points along its length aplurality of bearing rings 60 which rotatably engage and are supported on cradle-forming rollers 62 carried on a base frame 6ft-which extends the full length ofthe tube andsomewhat beyond the tube on each end.` Thel basename-64 is pivotally supported at one end, as at 66, andatthe other end;is. adjustably supported by any suitable means, typical means being shown at 68,

whereby one end of Athefrarnecan be vertically adjusted to controlthe inclination of the longitudinal axisl of the tube 22 with the horizontal. Usually the. angle of the tube. 212 with the horizontal is between about 4 and about.8, being generally in the neighborhood of '5 to 6.

.Means are provided for rotating the tube 22-about its longitudinalvaxis, and such means may, comprise a ring gear 70 secured to the tube, 'this gear being engaged by a pinion gear 72 extending from a speed changer 74 driven by a-motor 76. Of course, a variable speed motor may beutilized with or withoutugear reduction, and the rotation of the tube 22 can be. adjusted to any one of'a series of rotations per minute, for example,r 14, 17, 28, or 55. A thrust bearing 80. is associated with at least one set of cradle rollers 62 to talee up end thrust on the tube 22.v Also, the tube. 22, as best seenin Figures 3 and 7, is provided with a plurality Q longitudinally extending vanes 82for assisting inagitating` and tumbling the scrap as it passies along the length of the tube during treatments.`

The upper end of the tube 22, asrviewed in Fig. 2, is adapted to receive the scrap which is supplied thereto by wayof a conduit 84 which extends to a centrifugal feeding means 86. As seen inl-lig. 5, these feeding means S include a disc 8 8 carrying a plurality,v of impeller blades 90, the scrap being usually gravity fed to the center. of the impeller blades andbeing thrown out centrifugally as the disc 88 is driven from a shaft.v 92 by suitable motor means (not shown). The centrifugal feed mechanism S6iscarried on an end frame-94secured tothe base frame 64, and the centrifugal feed means 86 includes a round plate 96 having anY opening cut therethrough tov receive,l

the disc $8, and'impell'er blades 90 of the centrifugalfeed means, the casing 9,8,v ofthe centrifugal 'freed means bei-ng welded or otherwise joined to the opening intheplater96.

TheA plate 96 and the centrifugal feed means 86 are ment.

mounted f or movement toward and from thelend of the through Vholes in the end 1frame'94. Compression springs 102 on the bolts hold the plate 96 in close proximity to the -end of the tube 22 and the nuts on the bolts 100 are adjusted to insure .that theclearance between the disc 96 and theend of the tube is kept at a minimum. A conduit `104is connected to the plate 96 andprovides for exhausting the acid'vapor from the upper end of the tube22.UY 'i At the lowerend of thetube 22, I provide a short tubular portion 110 which is rigidly held by angles 112 011v thebase frame 64.V Azlabyrinthl seal, as best seen in Fig. 6, is provided between the tubular portion. 110 and the end .of .the tube 22 by means of a'ilange 114 secured to Ythe tube. A'conduit 116 provides for the introduction of acid vapor intothetube 22,2andV the' tubular portion 110 is provided with an openingv near. its bottom so that scrap moving 'down through the tube 22is discharged out of the opening and is conveyed away from the processing tube 22, for example, by means of a conveyorbelt 118. Itiwill be understood that the processing tube 22, and the various parts associated therewith and any conduits conducting theacid or acid vapor are made from acidresistant material of any suitable type.- I* have'found that Hastelloy B, an acid-resistant stainless steelalloy, is generally satisfactory.

Looking now at Figures 2 and 3, an important'part of the processing tube 22 is the careful control of heat along the full length-of thetube and in the variouszones hereinbefore described. This I achieve by surrounding the tube 22 with a heat-insulating hood or cover 122, made of'any suitable heat-resistant insulation, and constructed substantially in the form illustrated in Fig.'3 to surround theetop, sides, and bottom of the tube Y22fover its entire length. The heat-insulating hood 122is o'fa size'so that heaters 124 can `be positioned betweenthefsides of Vthe hood and the tube 22,*an independently controlled heater being associated with eachy of the various zones particularly illustrated in Fig. 7 of the drawings'. Preferably the heatersV 124 are electrical in character, land are ar,- ranged to be individually controlled so as .tofprovide'the heat specified inFig. 8. A thermostatw126 provided .Y in each zone, and as shown in Fig. 3,'v isconveniently positioned in close proximity tothe outer periphery' of. Vthe tube 22, and it is the temperature at this Vpoint which is referred to in the curves and temperature of 8;

In the operation of my improved process,'it will be understood that three variables are of particular importance. These are the concentration of theracid vapor used in the treatmennthe 4temperature maintainedV during the treatment, and the length of `time of the treat- I have already discussed the acid concentrations, and the temperature of treatment. Insofaras the length of time of the treatment is concerned, it will be recognized that increasing the angle of inclination of the processing tube 22, and the speed of rotation of the tube 22,' will reduce the treatment time. With acid concentrations and treating temperatures as described, the speed of rotation of the tube and the angle of inclination to the horizontal are adjusted so `that the total length of treating time ofthe scrap is between about two and about si?` ,Y minutes, and is usually in the neighborhood of four Vto tive minutes. 'l 'K It may be observed that, insofar as time of treatment is concerned with larger size material, forY example, material towards or above the 1%" particle size, the material moves more quickly through the treating tube with the ,tube angle andV rpm.l the same. Thus, with'treatment on larger particle size and becauseof the 'necessity for Lll) should be increased." With smaller particles of materialv towards $56, for example, the,V converse of the above is true. Y u. Y

Also, the volume of gasgjiovv should be mamtamed as slow as possible to allowV for the greatest penetration of Vthe vapor into the 'liber of the material, and to avoid the provision et improved apparatus for oxidizing cellulose or other vegetable fibers or fabric out of plastic scrap and particularly rubber scrap. The temperature utilized in the reclaiming process is'suiciently 10W so that the scrap itself is not oxidized or burnt. The treating processes can be maintained uniform over long treating periods, and can be utilized to satisfactorily reclaim scrap in production quantities. Thus, my improved apparatus is` char.- acterized by high eiciency and relatively low cost.

Throughout thedescriptioml have lreferred to the fact that I preferablyV passl the acid vapor over scrap in a direction opposite to the direction of movement of the scrap. Although this counter ow movement has distinct advantages, vit is possible to pass-the acid vapor over the scrap in the same directionV as the scrap is moving. Reference has also been made to the treatment of unvulcanized rubber and like plastic. However, the principles of my invention can be used to remove liber from vulcanized rubber andthe like. Also, I can separate cotton from wool and cotton from nylon; In general, IV

can remove any material which is attacked andhydrolized rather easily from any material which is not readilyat tacked and hydrolized by the acid vapor.'V 11: i

While in accordrwith the patent statutes, I haye specitically illustrated and described one bestknown embodiment of my invention, it is to be particularly understood that I am not to be limited thereto or thereby, but that the scope of my invention is defined in the appended claims.V Y Y i v l The present application is a division of my corpending application Serial No. 215,495,` led March 1,4, 1951, and entitled, Methods For Reclaiming Unvulcanized Rubber Scrap, Or The Like, Containing Fiben, Y

This application has now -matured into Patent; No. 2,701,268,

l claim:

In apparatus for reclaiming material futuri?liber-comV means for applying suction to the conduit, a stationary tubular section closed at its end at the lower ,end of the tube, a labyrinth seal between the'section and the tube, a conduit for supplying acid vapor to thesection, said section having a discharge `opening for 'the scrap, a stationary insulated hood surrounding the tubeyand a plurality of independently controllable vheating elementspositioned between the hood and the tube for establishing a plurality of heat zones along the length of the tube.v

References Cited in the lile of this patent i' UNITED VSTA'IES PATENTS 2,293,439 Lloyd A. i.i. YAllg. 1,78,` 1942 2,313,146 Hirschberger Q Mar. .'9, 1943 2,331,836 vI-Iirschberger v Oct; 12', V1943 2,498,398 Dasherv Apr; 3, 1946 2,543,315 Fabregat Apr. 15, 1947 

